Carburetor



United States Patent CARBURETOR Claude W. Miles, Jr., Warren, Melvin F.Sterner, Bloomfield Hills, and Neil M. Romeo, St. Clair Shores, Micln,assignors to Holley Carburetor Company, Warren,

Mich, a corporation of Michigan Filed Jan. 2, 1962, Ser. No. 163,568 2Claims. (Cl. 261-41) This invention relates to fuel systems for internalcombustion engines, and more particularly to a carburetor having aseparately attached fuel bowl.

Most carburetors of present design include either an integral fuelmetering system and fuel bowl or a separate fuel bowl which is attachedto the carburetor body, either directly or with a fuel metering body anda gasket seal therebetween. The area enclosed by this seal hasconventionally been the same as the cross-sectional area of theseparately attached fuel bowl.

While these prior art constructions have been generally acceptable, theyhave certain inherent characteristics that sometimes cause undesirableresults. Two of these results are (a) heat transfer from the throttlebody section to the fuel bowl and to the metering section and (b) thepossibility of fuel leakage due to the deterioration of the gaskets.

This invention is directly concerned with the above problems and has asits main objects the elimination of fuel leakage and the provision of acooling air space between the fuel bowl and the main carburetor body towhich it is attached. Since the metering section can also be a part ofthe proposed new separately attached fuel bowl, heat transfer to themetering section may likewise be reduced.

In the particular embodiment of the invention disclosed herein, the fuelleakage is eliminated by locating all gasket seals between thecarburetor and the separate fuel bowl well above the normal fuel levelin the bowl. Further, these seals are small in size and easy to install,service and inspect.

A further object of this invention is to provide a fuel bowlconstruction that is simple and easy to manufacture and which willprovide both a complete fuel metering system and a separate fuel bowl.That is, the fuel metering system may be an integral part of the fuelbowl, or it may be a separate body which is inserted into the fuel bowland fastened therein by any suitable means. The invention is alsoapplicable to a carburetor which includes an integral metering unit; inthat case, the separate fuel bowl would be provided without a fuelmetering system.

Further objects and advantages of the invention will become moreapparent when reference is made to the following description and theaccompanying drawings, wherein:

FIGURE 1 is a side elevational view of a carburetor embodying theinvention;

FIGURE 2 is a cross-sectional view taken on the plane of line 2-2 ofFIGURE 1 and looking in the direction of the arrows;

FIGURE 3 is a partial cross-sectional View taken on the plane of line 33of FIGURE 1 and looking in the direction of the arrows;

FIGURE 4 is a partial cross-sectional View taken on the plane of line4-4 of FIGURE 1 and looking in the direction of the arrows.

Referring to the drawings in greater detail, FIGURES l and 2 illustratea carburetor assembly mounted on the engine manifold 12. The fuel isforced into carburetor assembly 10 by the difference in pressure betweenmanifold vacuum and/ or venturi vacuum in the carburetor inductionpassage and substantially atmospheric pressure above the fuel in thefuel bowl assembly 14. At idle or off idle operation, the fuel flowsthrough jet 40, conduit 50 and finally through discharge port 54 and/ oridle transfer port 52. The main fuel at higher speeds flows through jet38, conduit 46 and main discharge nozzle 48. The transition frommanifold to venturi vacuum operation occurs as more air flows throughair passage 56 when throttle valve 58 pivoted on shaft 60 isprogressively opened by manual movement of throttle control lever 62against the force of spring 64 which tends to hold throttle valve 58closed. The above described structure and operation is, of course, Wellknown in the art.

FIGURES 1 and 2 also illustrate a fuel bowl assembly 14 having a mainbody 16 and a cover 20 fastened thereto by means of cover screws 28,with cover gasket 26 therebetween. As stated above, the fuel enterscarburetor assembly 10 through jets 38 and 40 located in meteringsection 37 of main body 16. The fuel bowl 14 also contains the usualfloat assembly 24 which rises or lowers with the fuel level in the floatchamber, thus controlling the inlet fuel valve 22 to admit only enoughfuel through the inlet fuel conduit 18 from the fuel pump to replacethat being used.

The above general operation is typical of most present day carburetorsystems. The invention now to be described comprises the fuel bowlassembly 14 and the manner in which it is attached to the carburetorassembly 10. It will be noted that gaskets 32, gasket 34 and bosses 35on the lower side of fuel bowl main body 16 are located between thecarburetor and fuel bowl assemblies. The thicknesses of the abovecomponents result in an air space between the fuel bowl assembly 14 andthe carburetor assembly Ill when the latter are fastened together by anysuitable means such as upper mounting screws 30 and lower mountingscrews 36, as shown in FIGURES 3 and 4.

In prior carburetor constructions there was no air space between thefuel bowl and the carburetor body. That is, the fuel bowl was eitherintegral with the carburetor body or, in the case of aseparately-attached fuel bowl, the gasket had an area equal to the areaof an entire side of the fuel bowl. In the case of the integral fuelbowl, heat was conducted through the carburetor and to the fuel bowl;this heat often resulted in vaporization of the fuel in the bowl,thereby causing a variety of problems such as fuel spilling out of thefuel bowl and onto the engine, excessive pressures above the fuel in thebowl, etc. Where a separate fuel bowl was attached with a large gasket,there was gasket area below the fuel level, and any deterioration of thegasket would result in leakage of the fuel from the bowl and onto theengine.

With the construction contemplated by this invention, the above problemsare virtually eliminated. It will be noted that the fuel bowl fasteningbolts 36 are short bolts that do not pass through the fuel chamber butthrough a flange on the bowl, as shown in FIGURE 4. It is more likely,as shown in FIGURES 1 and 3, that the longer top fastening bolts 30 dopass through the fuel chamber. However, in this case, the sealinggaskets 32 and gaskets at the heads of the bolts 30, if they areprovided, are disposed well above the normal fuel level L so that nosubstantial leakage can take place even if the gaskets shoulddeteriorate. The sealing gasket 34 having openings aligned with thepassages 40 and 42 in the bowl metering section and the main and idlefuel passages 46 and 50, respectively, in the carburetor body is alsolocated well above the fuel level and presents a minimum area forleakage, as compared to present constructions. Other fuel passages, suchas a pump discharge passage, could also be located above the fuel level.As already stated, the thickness of the gaskets 32 and 34 and the bosses35 provide an insulating air space between the carburetor body and thefuel bowl so that engine heat cannot be conducted 3 through thecarburetor and into the bowl to vaporize the fuel.

Although but one embodiment of the invention has been shown anddescribed, it is apparent that other modifications may be made withinthe scope of the appended claims.

What we claim as our invention is:

l. A carburetor for supplying motive fluid to an internal combustionengine, said carburetor comprising a main carburetor body having an airpassage with a venturi therein, a throttle plate positioned below saidventuri, idle and main fuel passages extending from one outer surface ofsaid carburetor body to idle and main fuel discharge ports,respectively, located in said air passage, a separate fuel reservoirhaving idle and main fuel passages supplied through jets located nearthe bottom of said reservoir and extending upwardly and outwardly to anouter surface of said fuel reservoir so as to be alignable with saidpassages in said carburetor body, a pair of bosses formed on said outersurface of said fuel reservoir having said passages, and means forsecuring said fuel reservoir to said carburetor body with said passagesin alignment, said means being disposed above the normal fuel level insaid fuel reservoir and including sealing elements having substantiallythe same thickness as said bosses so as to maintain an air space betweensaid carburetor body and said fuel reservoir after assembly thereof.

2. A carburetor for supplying motive fluid to an internal combustionengine, said carburetor comprising a main carburetor body having an airpassage with a venturi therein, a throttle plate positioned below saidventuri, idle and main fuel passages extending from one outer surface ofsaid carburetor body to idle and main fuel discharge ports,respectively, located in said air passage, a separate fuel reservoirhaving idle and main fuel passages supplied through jets located nearthe bottom of said reservoir and extending upwardly and outwardly to anouter surface of said fuel reservoir so as to be alignable with saidpassages in said carburetor body, at least one boss extending betweensaid outer surfaces of said fuel reservoir and said carburetor body at apoint below the normal fuel level in said reservoir, and means forsecuring said fuel reservoir to said carburetor body with said passagesin alignment, said means being disposed above said normal fuel level insaid fuel reservoir and including sealing elements having substantiallythe same thickness as said boss so as to maintain an air space betweensaid carburetor body and said fuel reservoir after assembly thereof.

References Cited in the file of this patent UNITED STATES PATENTS1,418,499 Washburn June 6, 1922 1,440,930 Mott Jan. 2, 1923 2,134,877Jedrzykowski Nov. 1, 1938 2,154,033 Cameron et al Apr. 11, 19392,271,116 Bracke J an. 27, 1942 2,392,681 Mallory Jan. 8, 1946 2,624,558Anderson Jan. 6, 1953 3,042,387 King July 3, 1962 FOREIGN PATENTS723,152 France Jan. 12, 1932 849,081 France Aug. 7, 1939

1. A CARBURETOR FOR SUPPLYING MOTIVE FLUID TO AN INTERNAL COMBUSTIONENGINE, SAID CARBURETOR COMPRISING A MAIN CARBURETOR BODY HAVING AN AIRPASSAGE WITH A VENTURI THEREIN, A THROTTLE PLATE POSITIONED BELOW SAIDVENTURI, IDLE AND MAIN FUEL PASSAGES EXTENDING FROM ONE OUTER SURFACE OFSAID CARBURETOR BODY TO IDLE AND MAIN FUEL DISCHARGE PORTS,RESPECTIVELY, LOCATED IN SAID AIR PASSAGE, A SEPARATE FUEL RESERVOIRHAVING IDLE AND MAIN FUEL PASSGES SUPPLIED THROUGH JETS LOCATED NEAR THEBOTTOM OF SAID RESERVOIR AND EXTENDING UPWARDLY AND OUTWARDLY TO ANOUTER SURFACE OF SAID FUEL RESERVOIR SO AS TO BE ALIGNABLE WITH SAIDPASSAGES IN SAID CARBURETOR BODY, A PAIR OF BOSSES FORMED ON SAID OUTERSURFACE OF SAID FUEL RESERVOIR HAVING SAID PASSAGES, AND MEANS FORSECURING SAID FUEL RESERVOIR TO SAID CARBURETOR BODY WITH SAID PASSAGESIN ALIGNMENT, SAID MEANS BEING DISPOSED ABOVE THE NORMAL FUEL LEVEL INSAID FUEL RESERVOIR AND INCLUDING SEALING ELEMENTS HAVING SUBSTANTIALLYTHE SAME THICKNESS ASD SAID BOSSES SO AS TO MAINTAIN AN AIR SPACEBETWEEN SAID CARBURETOR BODY AND SAID FUEL RESERVOIR AFTER ASSEMBLYTHEREOF.